Envelope of commensurability magnetoresistance oscillation in unidirectional lateral superlattices

The envelope of the commensurability magnetoresistance oscillation (Weiss o scillation) has been studied for lateral superlattices prepared from two-di mensional electron gas (2DEG) wafers with varying mobility mu. and spacer-l ayer thickness d(s). When the 2DEG has a high enough mu and a large enough d(s), the envelope is well described by the formula given by Peeters and Va silopoulos in a first-order perturbation theory [Phys. Rev. B 46, 4667 (199 2).]. For smaller mu or d(s), the oscillation diminishes faster than the fo rmula at lower B. The damping can be accounted for by an additional factor of the form [pi/(mu B-W)]/sinh[pi/(mu B-W)]. The parameter mu (W) is found to be proportional to the mean free path L of the 2DEG, and the coefficient of proportionality increases with d(s). The magnitude of mu (W), as well a s its dependence on d(s) and the electron areal density n(s), is close to t hat of mu (Q), the mobility corresponding to the total scattering time.